Fuse



Feb, 21, 1950 c. c. LAURITSEN 2,498fi43 FUSE Filed April 2, 1943 2 Sheets-Sheet l F/GJ.

INVENTOR CHARLES Z Z BY AT ORNEY 7 195% c. c. LAURH'SEN 2,498,43

BY HARLE mum sm 7a mmmg 5 ATTORNEY Patented Feb. 21, 1950 FUSE Charles C. Lauritsen, Pasadena, Caliifi, assignor to the United States of America as represented by the Secretary of the Navy Application April 2, 1943, Serial No. 481,646

'3 Claims.

This invention relates to fuzes and more particularly to a novel propeller-armed, impact-fired fuze which is simple and compact in construction and positive and reliable in operation. The new fuze may be handled safely and by reason of its propeller arming it may be used to advantage in rocket-propelled projectiles, and the like, wherein setback forces alone are too small to be employed safely for arming, and centrifugal forces for arming are lacking.

One object of the present invention resides in the provision of a propeller-armed fuze of novel construction including safety means for locking the propeller against rotation and operable by a force of setback to release the propeller.

Another object of the invention is to'provide a' novel fuze having a firing pin normally holding a safety gate in its safe position and movable endwise by the propeller to release the gate and expose one end of the pin at the nose of the fuze, and means operable on release of the gate to move it to an armed position at one end of the firing pin, whereby the pin is movable endwise into the gate upon impact with a target.

Still another object of the invention is to provide a fuze of the character described having novel safety means for insuring safe handling of the fuze and adapted to be released manually when the fuze is to be fired.

These and other objects of the invention may be better understood by reference to the accompanying drawings in conjunction with the following detailed description. In the drawings Fig. 1 is a longitudinal sectional view of one form of the new fuze;

Fig. 2 is a sectional view on the line 2-2 in Fig. 1;

Fig. 3 is a longitudinal sectional view of a modified form of the fuze, and

Fig. 4 is a sectional view on the line 4-4 in Fig. 3.

The fuze shown in Figs. 1 and 2 comprises a hollow cylindrical casing l having an externally threaded course adapted to be screwed into a suitable receptacle in the nose of an explosive projectile (not shown). At its rear end, the casing is internally threaded to receive a container l2 for the usual booster charge (not shown) through which the main charge in the projectile is detonated. A disc |3 in the casing closes the front end of the booster container l2 and has a central opening l4 through which the booster charge is ignited. A liner l5 abuts at its rear end against the disc l3 and is held in position in the casing by a set screw [6. In front of the liner of the casing, as shown at 25.

2 H5 is a guide plate I! which is held in position between the rear end of the liner and a shoulder H! in the casing, the guide plate, liner and disc |3 defining a chamber |5a.

A safety gate 2|] is mounted in the chamber |5a on a pivot 2|, so that the gate may swing transversely of the casing. Intermediate its ends, the gate is provided with a passage 22 for receiving a semi-cap (not shown) which may be of any desired form. A spring 23 is coiled around the pivot 2| and normally urges the safety gate clockwise (Fig. 2) against one side of a firing pin 24 slidable in guide plate II, the firing pin being threaded through the closed front end Thus, the rear end portion of the firing pin normally holds the safety gate 20 in a position wherein a semi-cap recess 22 is offset laterally from the firing pin and the opening l4, so as to prevent accidental firing of the semi-cap and explosion of the booster. In the front face of gate 20 is a plunger 26 which is urged against the adjacent face of guide plate I! by a compression spring 21 in the ate.

A hub 30 is keyed to the front end of the firing pin 24, as by means of a cotter pin 3 I, and carries a propeller 32. The propeller is normally locked against rotation by a pin 33 extending through the front end of the casing and secured to a setback pellet in the form of a collar 34 slidable endwise in the casing, the firing pin projecting loosely through the collar. A compression spring 35 is coiled around the firing pin within the collar and is seated at one end against guide plate I1 and at the opposite end against a shoulder in the collar, the spring urging the collar against the front end of the casing. The guide plate has a hollow boss 36 projecting into the spring 35 for locating it.

An annular shield 38 extends around the propeller 32 and is connected to an external flange 39 on the casing by screws 40. The shield 38 is formed with openings 4| which allow a flow of air against the propeller blades and through the shield. A safety wire 42 is bent around the shield When a projectile containing the fuze is to be fired, wire 42 is removed from the casing to release the set-back collar 34.

In firing the projectile, the force of set-back incident to its acceleration causes collar 34 to move rearwardly against spring 35, thereby withdrawing the pin 33 from hub and unlocking the propeller. The compression in spring 35 is such that the set-back collar 34 is operable to unlock the propeller in response to a relatively small force of set-back, such as that encountered in the firing of rockets. When the propeller 32 is unlocked, it is rotated aerodynamically incident to the flight of the projectile through the air and screws firing pin 24 forwardly in the casing to disengage the safety gate 20. Accordingly, the gate 20 is released and the spring =23gmoves it .inwardly against a stop to an armed position wherein the semi-cap opening 22 is alined with and directly under the firing pin. The gate is locked in .this position by the spring pressed plunger 26 which moves into an .opening 46 in the rear face of guide plate 11. When the projectile strikes a target, the impact on the exposed front end of the firing pin .24 moves the pin rearwardly against the semi-cap in opening 22, shearing the threads 25 on the firing pin. As a result, the semi-cap is fired and detonates the booster through opening IA.

The fuze shown in Figs. 3 and 4 comprises a generally frusto-conical casing 48 which is externally threaded at its rear end, as shown at 59, so that the casing is adapted to be screwed into a receptacle in the nose portion of a projectile (not shown). The fuze receptacle in the projectile may be sealed by a gasket 50 seated on an external shoulder of the casing 43. A container 5| is threaded in the rear end of the fuze casing for receiving a booster charge (not shown) operable to detonate the main charge in the projectile. The booster charge is adapted to be fired by a semi-cap 52 mounted in an axial passage in the fuze casing.

Intermediate its ends, the casing 48 has a transverse cylinder '54 containing a safety gate 55, the gate having an opening 56 extending lengthwise of the casing. The gate is urged inwardly in-the cylinder by a compression spring 5! disposed between the outer end of the gate and a plug 58 threaded in the cylinder.

A plunger 50 extends transversely into the fuze casing at right angles to the cylinder 54 and normally engages the inner end of gate 55 so as to hold the gate in a retracted position against spring 51. On its outer end, the plunger 60 has a head 5| engaging one end of a compression spring 62 coiled around the plunger in the fuze casing, the opposite .end of spring 62 being seated against a shoulder in the casing. The plunger 60 is formed intermediate its ends with an opening 53 extending lengthwise with respect to the casing and substantially'smaller in diameter than the gate opening '56. Near its inner end, the plunger 60 has a notch '64 which receives part of alock-ing pin -65 extending lengthwise of the casing and rotatable therein. Thepin 65 normally locks-the plunger -61] against spring $2 in position tohold the gate 55 retracted, but-the pin is rotatable through an angle of substantially 90 to release the plunger. Rotation-of'the pin 65 from its locking pQsition is normally prevented by an arm 66 on the pin which engages one side of a firing pin ,6! slidably mounted in an extension 8 t asin thr adedin the front end thereof. At its rearend, the ii-ring pinfi'l is reduced and end of the casing extension 68, and a hub H1 is screwed on the threaded portion of the pin and keyed to the pin, as shown at H. A propeller 12 is connected to hub 10 and is normally locked against rotation by a pin 73 projecting rearwardly through the plate 69 and secured in a setback collar 14 extending loosely around the firing pin. The collar 14 is slidable endwise in casing extension 68 and is urged against plate 69 by a compression spring 15 coiled around the firing pin between a shoulder in the casing extension 68 and a shoulder in the collar, whereby the locking pin l3 is held in position to prevent rotation of the propeller. A safety wire H5 extends transversely through casing extension 68 and engages the rear end of collar 14 to prevent accidental releasing of the propeller in handling the fuze, the safety wire being removable manually to unlock the set-back collar 14 when the fuze is to be fired.

An annular shield 18 extends around the propeller and has an inwardly turned portion 18a clamped between a shoulder on the casing extension 68 and a washer 19 on the front end of casing 48. The shield 18 is provided with openings for the passage of air through the shield when the projectile is in flight.

In operation, when a projectile containing the fuze is fired, the resulting force of set-back moves collar 14 rearwardly against spring 75 so as to Withdraw the locking pin I3 from the propeller. It will be understood that the spring 15 is sufiiciently yielding to permit movement of the setback collar under .the relatively small set-back forces encountered in rocket-propelled projectiles. When the propeller is thus released, it is rotated aerodynamically during the fiight of the projectile through the air and screws firing pin 61 forwardly in casing extension 68. As a result, the firing pin moves out of plunger opening 63 and disengages arm 66 of the locking pin 55, whereupon the plunger 60 is released and forced out of the casing by spring 62. The safety gate 55, therefore, is unlocked and moves inwardly to an armed position under the action of spring 57. In the armed position of the gate, the opening 55 is alined with the firing pin and the semi-cap 52. When the projectile strikes a target, the impact on the exposed front end of firing pin 6? forces the pin to the rear through gate opening 56 against the semi-cap, the impact being sufiicient to shear the threads on the front end portion of the firing pin. The semi-cap is then fired and detonates the booster charge in container 5!.

The set-back collar '14 prevents accidental rotation of the propeller due to a strong wind or to the blast from an adjacent rocket motor, and the collar may be locked in its safe position by the safety wire 16 at all times when the fuze is not in use. If desired, accidental movement of the pin 65 from its locking position may be prevented by an additional safety wire 82 extending transversely through the fuze casing and the locking pin. The firing pin 61 serves the dual function of firing the semi-cap 52 and preventing movement of the locking pin 65 and safety plunger 60 until the firing pin has been moved to its armed position by rotation of the propeller. If, for any reason, the arm 66 on locking pin 65 should fail to engage the firing pin, the latter continues to hold the plunger 60 in position to prevent movement of the safety gate to its armed position.

I claim:

1. A fuze comprising a hollow body, a firing pin threaded in the body, a propeller connected to the pin and operable aerodynamically to screw the pin to a retracted position in which the front end of the pin is exposed at the nose portion of the fuze, the pin being operable by impact of said end with a target, an inertia-operated collar oriented on the axis of the body through which collar the pin is movable, a locking element on the collar adapted to hold the propeller against rotation, and a spring coiled around the pin for pushing the collar and locking element toward the propeller to lock the propeller against rotation, the collar being movable against the spring by a force of setback to cause said element to release the propeller.

2. In a fuze having a firing pin, a safety gate coacting with the firing pin and having a percussion cap recess, a plunger adjacent one end of the gate and normally locking the gate in an unarmed position wherein said recess is offset from the firing pin, the plunger being held in its looking position by the firing pin, spring means for moving the plunger from its locking position and for moving the gate to an armed position to align said recess with the pin, means normally holding the plunger in its locking position and having a part engaging the firing pin to maintain said means operative, a propeller connected to the firing pin and rotatable aerodynamically to move the pin and thereby release the plunger and said means, means for normally locking the firing pin against rotation, and inertia-operated means for releasing the locking means.

3. In a fllZe having a firing pin, a safety gate coacting with the firing pin and having a percussion cap recess, a plunger adjacent one end of the gate and normally locking the gate in an unarmed position wherein said recess is ofiset from the firing pin, the plunger being held in its looking position by the firing pin, spring means for moving the plunger from its locking position and for moving the gate to an armed position to align said recess with the pin, means normally holding the plunger in its locking position and having a part engaging the firing pin to maintain said means operative, a releasable safety wire for securing said means against movement, a propeller connected to the firing pin and rotatable aerodynamically to move the pin and thereby release the plunger and said means, means for normally locking the firing pin against rotation, and inertia-operated means for releasing the locking means.

CHARLES C. LAURITSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

